Application and release valve device



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Patented Dec. 177, 1935 Y UNITED STATES PATENT oFFlcE APPLICATION AND RELEASE VALVE DEVICE John F. Craig, Upper Montclair, N. J., assignor to Y The Westinghouse Air Brake Company,V Wilmerding, Pa., a corporation of Pennsylvania i Application December 1, 1933, Serial No. 700,468

2 Claims.

This invention relates to uid pressure brakesA fpressure Ibrake equipment embodying a quick application and'release valve device constituting the invention; Fig. 2 is a sectional View taken on the line 2-2 of the quick application and releasevalve device shown inFig. 1; and Fig. 3 is a diagrammatic development View ci the brake valve device shown in Fig. 1. Y

The fluid pressure brake equipment shownY in Fig. 1 comprises a brake valve device I, a quick application and release valve device 2, a main reservoir 3 and a brake cylinder 4.

The brake valve device I is of the usual construction comprising a casing having a chamber 5 connected to a passage 6 leading tothe main reservoir 3, and containing a rotary Valve I adapted to be turned to Various brake controlling positions by means of a handle 8 operatively ccnnected to said rotary Valve through the medium Vof an'operating shaft 9, Y

The quick application and release valve device 2 comprises a casing consisting of a body member I6 having a chamber open at one end, and a cover member II secured to said-body member and closing the open end of said chamber, a gasket I2 being interposedV between said members.

A bushing I3 is contained in the chamber in the bodyV member 2 and is interposed between gasket I2 and a gasket I6 disposed against the closed end of said chamber. The bushing I3 is provided adjacent the outer end withV an annular collar I5 having a sliding iit with surface I6 of a recess formed in the body member 2 for positioning said bushing in said body member so as to form around said bushing an annular chamber I 'l which is connected to a pipe I8 leading to the brake cylinder 4. K Y

The bushing I3 is provided with an axial bore in which are slidably disposed a release piston I9 and an application. piston 20. piston I9 has at one side a chamber 2| open through a plurality'of radial, spaced Y.passages 22 in the bushing I 3 to the brake cylinder chamber I1, said piston being provided with an an- The release Y nular seat rib 23 adapted to engage and seal against the gasket I4 for closing communication from chamber 2l to an atmospheric exhaust passage 24. The seat rib 23 is of such length, that when it engages the gasket I4, the plurality of 5 passages 22 through the bushing I3 will not be lapped by the piston I9.

A chamber 25 is formed between the pistons I9 and 26 and is connected to a passage and pipe 26 leading to the brake valve device I, while a 10 chamber 21 is provided at the outer face of the application piston 20 and Vis connected through a plurality of radial passages 28 in the bushing I3 to the brake cylinder chamber Il.

A wall 29 is provided in the right hand end 15 of the bore through bushing I3 and a passage 36 is provided through said wall to' connect chamber 27 to a chamber 3l which is provided in the cover member il and connected to a passage and pipe 32 leading to the main reservoir pipe 6. 20

VA seat rib 4l is provided on thev wall 29 around Vthe passage 36 within chamber 3|, and a poppet type application valve 33, contained in chamber 3|, is normally pressed into sealing engagement with the seat rib lli by means of a spring 313, so 25 as to close communication from the main reservoir chamber 3l to chamber 21.

' The application valve 33 is preferably carried on a stem 35 which projects from the application piston through passage 36 in wall 29, said stem 30 being of such length as to prevent the application piston lapping passage A26 when the application valve 33 is seated against the seat rib fil. The wall 29 is provided on the left hand side with a plurality of raised portions 36 adapted to be 35 engaged by the application piston 2Q, upon full movementof said piston towards the right hand,

to prevent said piston closing communication through the passages 28 in the bushing I3.

' The application piston 29 is provided on the 40 Ilefthandside with a stem 31 adapted to limit movement of the release piston I9 towardA the right hand, so that saidl piston will not lap passage 26.

According to the preferred construction, the 45 lbushing I3, which contains thepistons I9 and 20, and the application Valvev33 carried by the piston 26, may be removed from or restored to the body member I0 manually, as a unit, when theV cover member II and gasket l2 are removed. 50

This facilitates cleaning of the device or renewal "of parts of the device which may become worn excessively, without having to interfere with or Vvremove the body member I0 from the pipes 32,

26 and I8. 55

In operation, fluid under pressure is supplied to the main reservoir 3 in the usual well known manner, and from thence flows through pipe 6 to rotary valve chamber 5 in the brake valve device I, and from pipe 6 through pipe 32 to the application valve chamber 3|.

With the brake valve device I in the normal or running position, as shown in Fig. l, the chamber 25 between the application piston 20 and release piston I9 is open to the atmosphere through passage and pipe 26, a cavity 38 in the rotary valve 1 and from thence through an atmospheric passage 39. With the chamber 25 thus vented and the application piston 20 in the normal position, the application valve 33 is seated by the `action of spring 34 and main reservoir pressure acting in chamber 3I, while with the release piston I9 in the normal position, the brake cylinder 4 is open to the atmosphere through pipe and passage I8, chamber I1 in the quick application and release valve device, through the plurality of passages 22 in the bushing I3, chamber 2I and from thence through the atmospheric exhaust passage 24.

If it is desired to effect an application of the brakes, the brake valve handle 8 is operated to turn the rotary valve 1 to application position, in which a port 40 in the rotary valve establishes communication between the application and release pipe 26 and the rotary valve chamber 5, as shown in Fig. 3 of the drawing. Fluid supplied from the main reservoir 3 to the rotary valve chamber 5 now ows through port 49 Vand pipe 26 to the chamber 25 between the application and release pistons 20 and I9 and urges said pistons away from each other. Due to the pressure acting to seat the application valve 33, which thereby opposes outward movement of the application piston 20, the release piston I9 is first operated and is moved to the position in which the seat rib 23 seals against gasket I4. Then when the pressure obtained in chamber 25 slightly exceeds the pressure acting to seat the application valve 33, the application piston 20 is moved toward the right hand and thereby moves 'said application valve away from the seat rib 4I.

With the application valve 33 unseated, fluid supplied from the main reservoir to chamber 3| flows to chamber 21 and from thence through the plurality of passages 28, chamber I1 and pipe I8 to brake cylinder 4, thus applying the brakes.

If it is desired to limit the degree of pressure thus obtained in the brake cylinder 4 to less than the pressure carried in the main reservoir 3, then, when the pressure obtained in chamber 25 corresponds substantially to that which it is desired to obtain in the brake cylinder 4, the brake valve handle 8 is turned from the application position to a lap position in which passage 26 is lapped by the rotary valve 5, as shown in Fig. 3 of the drawing. Then when the pressure obtained in the brake cylinder 4 and in chamber 21 acting on the right hand side of the application piston 20 slightly exceeds the control pressure in chamber 25, Ysaid piston is shifted towards the left hand, Which permits the application valve 33 'to seat and cut off further flow of iiuid under pressure to the brake cylinder. It will, therefore, be evident that the pressure in chamber 25 may be increased in a series of successive steps, and that the application piston 29 and valve y33 will operate to provide corresponding successive steps of increase in pressure in the brake cylinder 4.

Ir" the rate of increase in pressure in chamber 25, upon operation of the brake valve device I, is more rapid than the build up pressure in the 5 brake cylinder 4 and chamber 21, the application piston 20 will move into engagement with the raised portions 36, which prevents closing of the communication from chamber 21 to the plurality of passages 28, but if the capacity or" the appli- 10 cation valve is such as to' permit the pressure in brake cylinder 4 and chamber 21 to increase at Vsubstantially the same rate as the pressure is increased in chamber 25, then it will be evident that the application piston may not engage the 15 raised portions 35.

In effecting an application of brakes, fluid at the pressure in the brake cylinder 4 and acting in chamber I1, flows through the plurality of passages 22 to chamber 2l and therein acts on 20 the left hand face of the release piston I9 over the area of said piston outside of the seat rib 23, but the actuating pressure in chamber 25, acting over a greater area of the release piston, maintains the seat rib 23 in sealing engagement 25 with the gasket I4 and thereby prevents loss of fluid under pressure from the brake cylinder.

If it is desired to effect a release of the brakes after an application, the brake valve device I is turned to the release position, as shown in 30 Fig. 1. In this position, fluid under pressure is vented from chamber 25V to the atmosphere through passage and pipe 26, cavity 38 in rotary valve 1 and through the atmospheric exhaust passage 39. 35

When the pressure in chamber 25 acting to hold the release piston I9 in its left hand position is thus reduced to slightly below the opposing pressure in chamber 2|, said release piston is moved towards the right hand, thereby 40 opening communication from chamber 2I to the atmospheric exhaust passage 24, through which communication fluid under pressure is permitted to flow from the brake cylinder 4 by way of pipe and passage I8, chamber I1 and the plurality of 45 passages 22. Y

If only a partial release of the Vbrakes is desired, then when the pressure in chamber 25 is reduced to a degree substantially equal to the degree of pressure it is desired to retain in the 50 brake cylinder 4, the brake valve device I is turned from the release position to the lap position, in which passage 26 is lapped,'which prevents further venting of fluid under pressure from the chamber 25. When the brake cylin- 55 der pressure acting in chamber 2I then reduces to a degree slightly below the pressure in chamber 25, the piston I9 is moved towards the left until the seat rib 23 seals against the gasket I4, which prevents further venting of fluid un- 60 der pressure from the brake cylinder.

. It will, therefore, be evident that by moving the brake valve device between release and lap positions, the pressure in chamber 25 can be reduced in steps if desired, and that the release 65 piston I9 will operate according to the reduction in pressure in chamber 25 to permit corresponding steps ofA reduction in pressure in the brake cylinder 4. ,m

It will be noted that Ythe application and release valve device is simple and compact in construction, the working parts are readily accessible `for inspection, Acleaning or repairs and the der,vice functions according to the control pressure 75r vention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appendedV claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A valve device comprising a'casing having a chamber open at one end and closed at the other end and a passage opening into the closed end of said chamber, a cover member closing the open'end of said chamber and having a pressure chamberopening to the inner face of said cover, a gasket disposed in said casing around said pas? sage, another gasket disposed against the inner face of said cover member around said pressure chamber, and a valve assembly disposed in said casing chamber and removable therefrom by hand, said valve assemblycomprising a bushing disposed insaid casing chamber with opposite ends in sealing engagement with Vsaid gaskets, said bushing having a bore open at one end to said passage, a partition Wall adjacent the opposite end of said bore and having a central aperture open to said pressure chamber, a valve for controlling communication through said aperture, and a piston slidably mounted in said bore for controlling said valve.

2. A Valve device comprising a casing having a chamber open at one end and closed at the other end and a passage opening into the closed end of said chamber, a cover member closing the open end of said chamber and having a pressure chamber opening to the inner face of said cover, a gasket disposed in said casing around said passage, another gasket disposed against the inner 10 Vface of said cover member around saidV pressure chamber, a valve assembly disposed in said casing chamber and removable therefrom by hand, said valve assembly comprising a bushing disposed in said casing chamber with opposite ends in 15 sealing engagement with said gaskets, said bushing having a bore open at one end to said passage, a partition wall adjacent the opposite end of said bore and having a central aperature open to said pressure chamber, a valve for con- 20 trolling communication throughrsaid aperture, a piston slidably mounted in said bore for controlling vsaid valve, and another piston slidably mounted in said bore and movable into engage-V ment with the gasket at the closed end of said 25 casing chamberfor closing communication from said passage to the bore in said bushing.

JOHN F. CRAIG. 

